Chronic Renal Failure

AUTHOR INFORMATION

Author: Mauro Verrelli, MD, FRCPC, FACP, Assistant Professor, Department of Medicine, Section of Nephrology, University of Manitoba, Winnipeg, Canada

Mauro Verrelli, MD, FRCPC, FACP, is a member of the following medical societies: American College of Physicians-American Society of Internal Medicine, American Society of Nephrology, Canadian Medical Association, and Royal College of Physicians and Surgeons of Canada

Editor(s): Laura L Mulloy, DO, FACP, Professor of Medicine, Chief, Section of Nephrology, Hypertension and Transplantation Medicine, Glover/Mealing Eminent Scholar Chair in Immunology, Medical College of Georgia; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; George R Aronoff, MD, Director, Professor, Departments of Internal Medicine and Pharmacology, Section of Nephrology, Kidney Disease Program, University of Louisville School of Medicine; Rebecca J Schmidt, DO, FACP, FASN, Clinical Associate Professor of Medicine, West Virginia School of Osteopathic Medicine; Professor of Medicine, Section Chief, Department of Medicine, Section of Nephrology, West Virginia University School of Medicine; and Vecihi Batuman, MD, FACP, FASN, Professor of Medicine, Chief, Section of Nephrology, Tulane University School of Medicine; Professor, Renal-Hypertension Section, Department of Medicine, Tulane University Medical Center and Veterans Affairs Medical Center

 

INTRODUCTION

Background: The Kidney Disease Outcomes Quality Initiative (K/DOQI) of the National Kidney Foundation (NKF) defines chronic kidney disease (CKD) as either kidney damage or a decreased kidney glomerular filtration rate (GFR) of <60 mL/min/1.73 m² for 3 or more months. Whatever the underlying etiology, the destruction of renal mass with irreversible sclerosis and loss of nephrons leads to a progressive decline in GFR. The different stages of CKD form a continuum in time; prior to February 2002, no uniform classification of the stages of CKD existed. At that time, K/DOQI published a classification of the stages of CKD, as follows:

• Stage 1: Kidney damage with normal or increased GFR (>90 mL/min/1.73 m²)
• Stage 2: Mild reduction in GFR (60-89 mL/min/1.73 m²)
• Stage 3: Moderate reduction in GFR (30-59 mL/min/1.73 m²)
• Stage 4: Severe reduction in GFR (15-29 mL/min/1.73 m²)
• Stage 5: Kidney failure (GFR <15 mL/min/1.73 m² or dialysis)

The K/DOQI definition and the classification of CKD allow better communication and intervention at the different stages.

Pathophysiology: Approximately 1 million nephrons are present in each kidney, each contributing to the total GFR. Regardless of the etiology of renal injury, with progressive destruction of nephrons, the kidney has an innate ability to maintain GFR by hyperfiltration and compensatory hypertrophy of the remaining healthy nephrons. This nephron adaptability allows for continued normal clearance of plasma solutes such that substances such as urea and creatinine start to show significant increases in plasma levels only after total GFR has decreased to 50%, when the renal reserve has been exhausted. The plasma creatinine value will double with a 50% reduction in GFR. A rise in plasma creatinine from a baseline value of 0.6 mg/dL to 1.2 mg/dL in a patient, although still within the reference range, actually represents a loss of 50% of functioning nephron mass.

The residual nephron hyperfiltration and hypertrophy, although beneficial for the reasons noted, has been hypothesized to represent a major cause of progressive renal dysfunction. This is believed to occur because of increased glomerular capillary pressure, which damages the capillaries and leads initially to focal and segmental glomerulosclerosis and eventually to global glomerulosclerosis. This hypothesis has been based on studies of five-sixths nephrectomized rats, which develop these lesions that are identical to those observed in humans with CKD.

Factors other than the underlying disease process and glomerular hypertension that may cause progressive renal injury include the following:

• Systemic hypertension
• Acute insults from nephrotoxins or decreased perfusion
• Proteinuria
• Increased renal ammoniagenesis with interstitial injury
• Hyperlipidemia
• Hyperphosphatemia with calcium phosphate deposition
• Decreased levels of nitrous oxide

Frequency:

• In the US: The US Renal Data System (USRDS) has shown a dramatic increase in patients with CKD who require chronic dialysis or transplantation. In 1999, there were 340,000 such patients, but, by 2010, this number is projected to reach 651,000. CKD, particularly at the stage requiring renal replacement therapy (dialysis or transplantation), is already a major burden to health care resources, and this will only worsen in time.

  Because of the nonuniform definition of kidney disease prior to February 2002, among other factors, most patients with earlier CKD stages have not been recognized or adequately treated. The Third National Health and Examination Survey (NHANES III) estimated that the prevalence of CKD in adults in the United States was 11% (19.2 million): 3.3% (5.9 million) had stage 1, 3.0% (5.3 million) had stage 2, 4.3% (7.6 million) had stage 3, 0.2% (400,000) had stage 4, and 0.2% (300,000) had stage 5.

• Internationally: The incidence rates of end-stage renal disease (ESRD) have increased steadily internationally since 1989. The United States has the highest incident rate of ESRD, followed by Japan. Japan has the highest prevalence per million population, with the United States taking second place.

Mortality/Morbidity: CKD is a major cause of morbidity and mortality, particularly at the later stages. Although the diabetic population is at highest risk, in the United States, the general hemodialysis and peritoneal dialysis populations have 2.0 hospital admissions per patient per year; patients who have a renal transplant have an average of 1.0 hospital admissions per year. The 5-year survival rate for a patient undergoing chronic dialysis in the United States is approximately 35%. This is approximately 25% in patients with diabetes. The most common cause of death in the dialysis population is cardiovascular disease.

Race:

• CKD affects all races, but, in the United States, a significantly higher incidence of ESRD exists in blacks as compared to whites; the incident rate for blacks is nearly 4 times that for whites.

Sex:

• In NHANES III, the distribution of estimated GFRs for the CKD stages was similar in both sexes. Nonetheless, the USRDS 2004 Annual Data Report reveals that the incident rate of ESRD cases is higher for males with 409 per million population in 2002 compared to 276 for females.

Age: CKD is found in persons of all ages. Nonetheless, in the United States, the highest incidence rate of ESRD occurs in patients older than 65 years. Besides diabetes mellitus and hypertension, age is an independent major predictor of CKD. Of the US population older than 65 years without diabetes mellitus or hypertension, 11% had CKD stage 3 or worse according to the NHANES III. The geriatric population is the most rapidly growing kidney failure (CKD stage 5) population in the United States.

Note that after age 30 years progressive physiological glomerulosclerosis occurs, with GFR (and creatinine clearance [CrCl) falling linearly at a rate of approximately 8 cc/min/1.73 m²/y from a maximal GFR of 140 cc/min/1.73 m². Aging also results in concomitant progressive physiological decrease in muscle mass such that daily urinary creatinine excretion also decreases; this combination of factors results in constant serum creatinine values over time in a given individual, despite a decrease in CrCl (and GFR).

Therefore, a serum creatinine value of 0.8 mg/dL in a 70-kg, 25-year-old man versus one who is 80 years old represents a CrCl of 140 cc/min and 73 cc/min, respectively. What can appear as only mild renal impairment in an 80-year-old, 70-kg man with a pathologically elevated serum creatinine of 2.0 mg/dL actually represents severe renal impairment when the CrCl is calculated to be 29 cc/min. Therefore, a CrCl must be calculated simply by using the Cockcroft-Gault formula (see

Other Tests) in elderly people so that appropriate drug dosing adjustments can be made and nephrotoxins can be avoided in patients who have more extensive CKD than would be suggested by the serum creatinine alone.

CLINICAL

History: Patients with CKD stage 3 or lower (GFR >30 mL/min) generally are asymptomatic and do not experience clinically evident disturbances in water or electrolyte balance or endocrine/metabolic derangements. Generally, these disturbances clinically manifest with CKD stages 4 and 5 (GFR <30 mL/min). Uremic manifestations in patients with CKD stage 5 are believed to be primarily secondary to an accumulation of toxins, the identity of which is generally not known.

• Hyperkalemia usually develops when GFR falls to less than 20-25 mL/min because of the decreased ability of the kidneys to excrete potassium. It can be observed sooner in patients who ingest a potassium-rich diet or if serum aldosterone levels are low, such as in type IV renal tubular acidosis commonly observed in people with diabetes and commonly observed with use of angiotensin-converting enzyme (ACE) inhibitors or nonsteroidal anti-inflammatory drugs (NSAIDs). Hyperkalemia in CKD can be aggravated by an extracellular shift of potassium, such as that occurs in the setting of acidemia or from lack of insulin.

• Metabolic acidosis often is mixed, non–anion gap and anion gap, the latter observed generally with CKD stage 5 but with the anion gap generally not higher than 20 mEq/L. In CKD, the kidneys are unable to produce enough ammonia in the proximal tubules to excrete the endogenous acid into the urine in the form of ammonium. In CKD stage 5, accumulation of phosphates, sulphates, and other organic anions are the cause of the small anion gap.

• Extracellular volume expansion and total-body volume overload results from failure of sodium and free water excretion. This generally becomes clinically manifest when GFR falls to less than 10-15 mL/min, when compensatory mechanisms have become exhausted. Patients present with peripheral and, not uncommonly, pulmonary edema and hypertension. At a higher GFR, excess sodium and water intake could result in a similar picture if the ingested amounts of sodium and water exceed the available potential for compensatory excretion.

• Normochromic normocytic anemia principally develops from decreased renal synthesis of erythropoietin, the hormone responsible for bone marrow stimulation for red blood cell (RBC) production. It becomes more severe as GFR progressively decreases with the availability of less viable renal mass. No reticulocyte response occurs. RBC survival is decreased, and tendency of bleeding is increased from the uremia-induced platelet dysfunction.

• Secondary hyperparathyroidism develops because of hypocalcemia, decreased renal synthesis of 1,25-dihydroxycholecalciferol (1,25-dihydroxyvitamin D, or calcitriol), and hyperphosphatemia.

• Calcium and calcitriol are primary feedback inhibitors; hyperphosphatemia is a stimulus to parathyroid hormone (PTH) synthesis and secretion.

• Phosphate retention begins in early CKD; when GFR falls, less phosphate is filtered and excreted, but serum levels do not rise initially because of increased PTH secretion, which increases renal excretion. As GFR falls toward CKD stages 4 and 5, hyperphosphatemia develops from the inability of the kidneys to excrete the excess dietary intake. Hyperphosphatemia suppresses the renal hydroxylation of inactive 25-hydroxyvitamin D to calcitriol, so serum calcitriol levels are low when the GFR is less than 30 mL/min.

• Hypocalcemia develops primarily from decreased intestinal calcium absorption because of low plasma calcitriol levels and possibly from calcium binding to elevated serum levels of phosphate.

• Low serum calcitriol levels, hypocalcemia, and hyperphosphatemia have all been demonstrated to independently trigger PTH synthesis and secretion. As these stimuli persist in CKD, particularly in the more advanced stages, PTH secretion becomes maladaptive and the parathyroid glands, which initially hypertrophy, become hyperplastic. The persistently elevated PTH levels exacerbate hyperphosphatemia from bone resorption of phosphate.

• If serum levels of PTH remain elevated, a high–bone turnover lesion, known as osteitis fibrosa, develops. This is one of several bone lesions, which as a group are commonly known as renal osteodystrophy. These lesions develop in patients with severe CKD and are common in those with ESRD. Osteomalacia and adynamic bone disease are the 2 other lesions observed. The former, observed primarily from aluminum accumulation, is markedly less common than the latter, whose etiology is unclear. Adynamic bone disease represents the predominant bone lesion in patients on chronic peritoneal dialysis and is increasing in frequency. Dialysis-related amyloidosis from beta2-microglobulin accumulation in patients who have required chronic dialysis for at least 8-10 years is another form of bone disease that manifests with cysts at the ends of long bones.

• Other manifestations of uremia in ESRD, many of which are more likely in patients who are inadequately dialyzed, include the following:

• Pericarditis - Can complicate with cardiac tamponade, possibly resulting in death

• Encephalopathy - Can progress to coma and death

• Peripheral neuropathy

• Restless leg syndrome

• GI symptoms - Anorexia, nausea, vomiting, diarrhea

• Skin manifestations - Dry skin, pruritus, ecchymosis

• Fatigue, increased somnolence, failure to thrive

• Malnutrition

• Erectile dysfunction, decreased libido, amenorrhea
• Platelet dysfunction with tendency to bleeding

Physical: The physical examination often is not very helpful but may reveal findings characteristic of the condition underlying CKD (eg, lupus, severe arteriosclerosis, hypertension) or complications of CKD (eg, anemia, bleeding diathesis, pericarditis).

Causes:

• Vascular disease - Renal artery stenosis, cytoplasmic pattern antineutrophil cytoplasmic antibody (C-ANCA)–positive and perinuclear pattern antineutrophil cytoplasmic antibody (P-ANCA)–positive vasculitides, antineutrophil cytoplasmic antibody (ANCA)–negative vasculitides, atheroemboli, hypertensive nephrosclerosis, renal vein thrombosis

• Primary glomerular disease - Membranous nephropathy, immunoglobulin A (IgA) nephropathy, focal and segmental glomerulosclerosis (FSGS), minimal change disease, membranoproliferative glomerulonephritis, rapidly progressive (crescentic) glomerulonephritis

• Secondary glomerular disease - Diabetes mellitus, systemic lupus erythematosus, rheumatoid arthritis, mixed connective tissue disease, scleroderma, Goodpasture syndrome, Wegener granulomatosis, mixed cryoglobulinemia, postinfectious glomerulonephritis, endocarditis, hepatitis B and C, syphilis, human immunodeficiency virus (HIV), parasitic infection, heroin use, gold, penicillamine, amyloidosis, light chain deposition disease, neoplasia, thrombotic thrombocytopenic purpura (TTP), hemolytic-uremic syndrome (HUS), Henoch-Schönlein purpura, Alport syndrome, reflux nephropathy

• Tubulointerstitial disease - Drugs (eg, sulfa, allopurinol), infection (viral, bacterial, parasitic), Sjögren syndrome, chronic hypokalemia, chronic hypercalcemia, sarcoidosis, multiple myeloma cast nephropathy, heavy metals, radiation nephritis, polycystic kidneys, cystinosis

• Urinary tract obstruction - Urolithiasis, benign prostatic hypertrophy, tumors, retroperitoneal fibrosis, urethral stricture, neurogenic bladder

 

DIFFERENTIALS

Acute Renal Failure

WORKUP

Lab Studies:

• Elevated serum urea and creatinine

• Hyperkalemia, low serum bicarbonate, hypocalcemia, hyperphosphatemia, hyponatremia (in ESRD with free-water excess)

• Hypoalbuminemia in patients who are nephrotic and/or malnourished

• Normochromic normocytic anemia - Other underlying causes of anemia should be ruled out.

• Urinalysis - Dipstick proteinuria may suggest glomerular or a tubulointerstitial problem.

• Urine sediment finding of RBCs, RBC casts, suggests proliferative glomerulonephritis. Pyuria or/and WBC casts are suggestive of interstitial nephritis (particularly if eosinophiluria is present) or urinary tract infection.

• Spot urine collection for total protein-to-creatinine ratio allows reliable approximation (extrapolation) of total 24-hour urinary protein excretion. A value of greater than 2.0 g is considered to be within glomerular range, and a value greater than 3.0-3.5 g is within the nephrotic range; less than 2.0 is characteristic of tubulointerstitial problems.

• Twenty-four–hour urine collection for total protein and CrCl

• Serum and urine protein electrophoresis to screen for a monoclonal protein possibly representing multiple myeloma

• Antinuclear antibodies (ANA), double-stranded DNA antibody levels to screen for systemic lupus erythematosus

• Serum complement levels - May be depressed with some glomerulonephritides

• C-ANCA and P-ANCA levels - Helpful if positive in diagnosis of Wegener granulomatosis and polyarteritis nodosa or microscopic polyangiitis, respectively

• Anti–glomerular basement membrane (anti-GBM) antibodies - Highly suggestive of underlying Goodpasture syndrome

• Hepatitis B and C, HIV, Venereal Disease Research Laboratory (VDRL) serology - Conditions associated with some glomerulonephritides

Imaging Studies:

• Plain abdominal x-ray - Particularly useful to look for radio-opaque stones or nephrocalcinosis

• Intravenous pyelogram - Not commonly used because of potential for intravenous contrast renal toxicity; often used to diagnose renal stones

• Renal ultrasound - Small echogenic kidneys are observed in advanced renal failure. Kidneys usually are normal in size in advanced diabetic nephropathy, where affected kidneys initially are enlarged from hyperfiltration. Structural abnormalities, such as polycystic kidneys, also may be observed. This is a useful test to screen for hydronephrosis, which may not be observed in early obstruction, or involvement of the retroperitoneum with fibrosis, tumor, or diffuse adenopathy. Retrograde pyelogram may be indicated if a high index of clinical suspicion for obstruction exists despite a negative study finding.

• Renal radionuclide scan - Useful to screen for renal artery stenosis when performed with captopril administration but is unreliable for GFR of less than 30 cc/min; also quantitates differential renal contribution to total GFR

• CT scan - CT scan is useful to better define renal masses and cysts usually noted on ultrasound. Also, it is the most sensitive test for identifying renal stones. IV contrast-enhanced CT scans should be avoided in patients with renal impairment to avoid acute renal failure; this risk significantly increases in patients with moderate-to-severe CKD. Dehydration also markedly increases this risk.

• MRI is very useful in patients who require a CT scan but who cannot receive intravenous contrast. It is reliable in the diagnosis of renal vein thrombosis, as are CT scan and renal venography. Magnetic resonance angiography also is becoming more useful for diagnosis of renal artery stenosis, although renal arteriography remains the criterion standard.

• Voiding cystourethrogram (VCUG) - Criterion standard for diagnosis of vesicoureteral reflux

Other Tests:

• The Cockcroft-Gault formula for estimating CrCl should be used routinely as a simple means to provide a reliable approximation of residual renal function in all patients with CKD. The formulas are as follows:

• CrCl (male) = ([140-age] X weight in kg)/(serum creatinine X 72)

• CrCl (female) = CrCl (male) X 0.85

• Alternatively, the Modification of Diet in Renal Disease (MDRD) Study equation could be used to calculate GFR. This equation does not require a patient's weight (Levey, 1999).

Procedures:

• Percutaneous renal biopsy currently is performed most often with ultrasound guidance and the use of a mechanical gun. It generally is indicated when renal impairment and/or proteinuria approaching the nephrotic range are present and the diagnosis is unclear after appropriate other workup. It is not indicated in the setting of small echogenic kidneys on ultrasound because these are severely scarred and represent chronic irreversible injury. The most common complication of this procedure is bleeding, which can be life threatening in a minority of occurrences.

• Surgical open renal biopsy can be considered when the risk of renal bleeding is felt to be great, occasionally with solitary kidneys, or when percutaneous biopsy is technically difficult to perform.

Histologic Findings: Renal histology in CKD reveals findings compatible with the underlying primary renal diagnosis and, generally, findings of segmental and globally sclerosed glomeruli and tubulointerstitial atrophy, often with tubulointerstitial mononuclear infiltrates.

TREATMENT

Medical Care: Medical care of the patients with CKD should focus on the following:

• Delaying or halting progression of CKD

• Treatment of the underlying condition if possible
• Aggressive blood pressure control to target values per current guidelines
• Use of ACE inhibitors as tolerated, with close monitoring for renal deterioration and for hyperkalemia (avoid in advanced renal failure, bilateral renal artery stenosis [RAS], RAS in a solitary kidney)
• Aggressive glycemic control per the American Diabetes Association (ADA) recommendations; target HbA1C <7.0%
• Protein restriction - Controversial
• Treatment of hyperlipidemia to target levels per current guidelines
• Avoidance of nephrotoxins - IV radiocontrast, nonsteroidal anti-inflammatory agents, aminoglycosides

• Treating pathologic manifestations of CKD, including the following:

• Anemia with erythropoietin
• Hyperphosphatemia with dietary phosphate binders and dietary phosphate restriction
• Hypocalcemia with calcium supplements +/- calcitriol
• Hyperparathyroidism with calcitriol or vitamin D analogs
• Volume overload with loop diuretics or ultrafiltration
• Metabolic acidosis with oral alkali supplementation
• Uremic manifestations with chronic renal replacement therapy (hemodialysis, peritoneal dialysis, or renal transplantation): Indications include severe metabolic acidosis, hyperkalemia, pericarditis, encephalopathy, intractable volume overload, failure to thrive and malnutrition, peripheral neuropathy, intractable gastrointestinal symptoms, and GFR less than 10 mL/min.
• Cardiovascular complications

• Timely planning for chronic renal replacement therapy

• Early education regarding natural disease progression, different dialytic modalities, renal transplantation, patient option to refuse or discontinue chronic dialysis
• Timely placement of permanent vascular access (arrange for surgical creation of primary arteriovenous fistula, if possible, and preferably at least 6 months in advance of anticipated date of dialysis)
• Timely elective peritoneal dialysis catheter insertion
• Timely referral for renal transplantation

Consultations:

• Early nephrology referral (decreases morbidity and mortality)

• Renal dietitian

• Vascular surgery for permanent vascular access

• General surgery for peritoneal catheter placement

• Referral to renal transplant center

Diet:

• Protein restriction early in CKD as a means to delay a decline in GFR is controversial; however, as the patient approaches CKD stage 5, this is recommended to delay the onset of uremic symptoms. Patients with CKD who already are predisposed to becoming malnourished are at higher risk for malnutrition with overly aggressive protein restriction. Malnutrition is a well-established predictor of increased morbidity and mortality in the ESRD population and must be avoided if possible.

• Phosphate restriction starting early in CKD

• Potassium restriction

• Sodium and water restriction as needed to avoid volume overload

 

MEDICATION

Drug Category: Phosphate-lowering agents -- Hyperphosphatemia is treated with dietary phosphate binders and dietary phosphate restriction. Hypocalcemia is treated with calcium supplements and possibly calcitriol. Hyperparathyroidism is treated with calcitriol or vitamin D analogs.

Drug Name
Calcium acetate (Calphron, PhosLo) -- For treatment of hyperphosphatemia in CKD. Combines with dietary phosphorus to form insoluble calcium phosphate, which is excreted in feces.

Adult Dose
1334 mg PO with each meal; increase to bring serum phosphate value to 6 mg/dL as long as hypercalcemia does not develop; may require as much as 2668 mg

Pediatric Dose
Not established

Contraindications
Hypercalcemia; hypophosphatemia; renal calculi

Interactions
May increase effect of quinidine; may decrease effects of tetracyclines, atenolol, salicylates, iron salts, and fluoroquinolones; IV administration antagonizes effects of verapamil; large intakes of dietary fiber may decrease calcium absorption and levels

Pregnancy
C - Safety for use during pregnancy has not been established.

Precautions
Hypercalcemia or hypercalcuria may occur when therapeutic amounts are administered

Drug Name
Calcium carbonate (Caltrate, Oystercal) -- For treatment of hyperphosphatemia or as a calcium supplement in CKD. Successfully normalizes phosphate concentrations in patients with CKD. Combines with dietary phosphate to form insoluble calcium phosphate, which is excreted in feces. Marketed in a variety of dosage forms and is relatively inexpensive.

Adult Dose
1-2 g PO divided bid/qid; with meals as a phosphorous binder; between meals as a calcium supplement

Pediatric Dose
45-65 mg/kg/d PO divided qid

Contraindications
Renal calculi; hypercalcemia; hypophosphatemia; digitalis toxicity

Interactions
May decrease effects of tetracyclines, atenolol, salicylates, iron salts, and fluoroquinolones; IV administration antagonizes effects of verapamil; large intakes of dietary fiber may decrease calcium absorption and levels

Pregnancy
C - Safety for use during pregnancy has not been established.

Precautions
Hypercalcemia or hypercalcuria may occur when therapeutic amounts are administered

Drug Name
Calcitriol (Rocaltrol, Calcijex) -- Used to suppress parathyroid production and secretion in secondary hyperparathyroidism and for treatment of hypocalcemia in CKD by increasing intestinal calcium absorption.

Adult Dose
0.25 mcg PO qd/qod
0.5 mcg IV qd 3 times per wk
Increase at 4- to 8-wk intervals by 0.25-mcg/d to achieve target PTH level and to maintain serum calcium levels at 9-10 mg/dL

Pediatric Dose
Initial: 15 ng/kg/d PO
Maintenance: 5-40 ng/kg/d PO

Contraindications
Documented hypersensitivity; hypercalcemia; malabsorption syndrome

Interactions
Cholestyramine and colestipol decrease absorption; magnesium-containing antacids and thiazide diuretics can increase calcitriol effects

Pregnancy
C - Safety for use during pregnancy has not been established.

Precautions
Adequate response to calcitriol in improving hypocalcemia depends on adequate dietary calcium intake; serum calcium phosphate product must not exceed 70 mg/dL to minimize metastatic tissue and blood vessel calcification; avoid hypercalcemia

Drug Name
Doxercalciferol (Hectorol) -- A vitamin D analog (1-alpha-hydroxyergocalciferol) that does not require activation by the kidneys. Indicated for the treatment of secondary hyperparathyroidism in end-stage renal disease.

Adult Dose
10 mcg PO 3 times/wk at dialysis; adjust dose as needed to lower blood iPTH to 150-300 pg/mL; increase dose by 2.5 mcg/8 wk if iPTH is not lowered by 50% and fails to reach the target range; not to exceed 20 mcg/3 times/wk
Alternatively, 4 mcg IV 3 times/wk; may adjust dose by 1-2 mcg/8 wk to maintain iPTH levels

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; recent hypercalcemia or hyperphosphatemia

Interactions
Coadministration with drugs that impair absorption of fat soluble vitamins (eg, cholestyramine) may decrease doxercalciferol absorption; increases the risk of hypermagnesemia with magnesium-containing products (eg, antacids)

Pregnancy
B - Usually safe but benefits must outweigh the risks.

Precautions
May cause headache, malaise, dyspnea, or hypercalcemia; caution in renal osteodystrophy with hyperphosphatemia (potential for metastatic calcification)

Drug Name
Lanthanum carbonate (Fosrenal) -- Noncalcium, nonaluminum phosphate binder indicated for reduction of high phosphorus levels in patients with end-stage renal disease. Directly binds dietary phosphorus in upper GI tract, thereby inhibiting phosphorus absorption.

Adult Dose
Initial: 250-500 mg PO tid pc (chewable tabs); adjust dose q2-3wk to target serum phosphorus level
Maintenance: 500-1000 mg PO tid pc

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; bowel obstruction; hypophosphatemia

Interactions
Drugs known to interact with antacids (eg, alendronate, amprenavir, ciprofloxacin, itraconazole, tetracycline, thyroid hormones) should not be administered within 2 h

Pregnancy
C - Safety for use during pregnancy has not been established.

Precautions
Deposited into developing bone, including growth plate (long-term effects unknown); common adverse effects typically diminish over time but include headache, abdominal pain, nausea, diarrhea, constipation, and vomiting; in clinical trials, dialysis graft occlusion occurred more frequently than with placebo; caution with GI motility diseases (eg, Crohn disease, ulcerative colitis) or recent GI surgery

Drug Name
Sevelamer (Renagel) -- Indicated for the reduction of serum phosphorous in patients with ESRD. Binds dietary phosphate in the intestine, thus inhibiting its absorption. In patients on hemodialysis, it decreases the frequency of hypercalcemic episodes relative to patients on calcium acetate treatment.

Adult Dose
Initial: 800-1600 mg PO tid with meals
Maintenance: Increase or decrease by 400-800 mg per meal q2wk to maintain serum phosphorous at 6 mg/dL or less

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; bowel obstruction; hypophosphatemia

Interactions
None reported

Pregnancy
C - Safety for use during pregnancy has not been established.

Precautions
Caution in patients with dysphagia, severe GI tract motility disorders, or swallowing disorders; does not contain calcium or alkali supplementation (monitor serum calcium, bicarbonate, and chloride levels)

Drug Name
Paricalcitol (Zemplar) -- For treatment of secondary hyperparathyroidism in ESRD. Reduces PTH levels, stimulates calcium and phosphorous absorption, and stimulates bone mineralization.

Adult Dose
0.04-0.1 mcg IV bolus 3 times per wk; adjust dose based on PTH levels

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; hypercalcemia; vitamin D toxicity

Interactions
Do not use phosphate or vitamin D-related compounds concomitantly with paricalcitol; caution if administered with digoxin (digitalis toxicity is potentiated by hypercalcemia)

Pregnancy
C - Safety for use during pregnancy has not been established.

Precautions
Caution in breastfeeding; adverse effects include GI tract distress, dry mouth, lightheadedness, edema, chills, or fever

Drug Category: Growth factors -- Used to treat anemia of CKD by stimulating RBC production.

Drug Name
Epoetin alfa (Epogen, Procrit) -- Stimulates division and differentiation of committed erythroid progenitor cells. Induces release of reticulocytes from bone marrow into blood stream.

Adult Dose
50-150 U/kg IV/SC 3 times per wk

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; uncontrolled hypertension

Interactions
None reported

Pregnancy
C - Safety for use during pregnancy has not been established.

Precautions
Caution in porphyria, hypertension, and history of seizures; decrease dose if hematocrit increase exceeds 4 U in any 2-wk period

Drug Category: Iron salts -- Nutritionally essential inorganic substances used to treat anemia.

Drug Name
Ferrous sulfate (Feosol, Feratab, Slow FE) -- Used as a building block for hemoglobin synthesis in treating anemia of CKD with erythropoietin.

Adult Dose
325 mg PO qd/tid

Pediatric Dose
<15 kg: 5 mg/kg/d PO
15-30 kg: 160 mg PO qd

Contraindications
Documented hypersensitivity

Interactions
Absorption is enhanced by ascorbic acid; interferes with tetracycline absorption; food and antacids impair absorption

Pregnancy
A - Safe in pregnancy

Precautions
GI tract upset; iron toxicity is observed with ingestion of large amount and can be fatal, especially in children; parenteral (IV) administration may cause several reactions, including headaches, malaise, fever, generalized lymphadenopathy, arthralgia, and urticaria; can cause severe anaphylaxis; other reactions include phlebitis at infusion site

Drug Name
Iron dextran (DexFerrum, InFed) -- Used to treat microcytic, hypochromic anemia resulting from iron deficiency when oral administration is unfeasible or ineffective.
Utilized to replenish iron stores in individuals on erythropoietin therapy who cannot take or tolerate oral iron supplementation.
A 0.5-mL (0.25 mL in children) test dose should be administered prior to starting therapy.
Available as 50 mg iron/mL (as dextran).

Adult Dose
>50 kg: 100 mg IV (2 mL); not to exceed 2 mL/d

Pediatric Dose
5-10 kg: 50 mg IV (1 mL)

Contraindications
Documented hypersensitivity; anemias that are not involved with iron deficiency; hemochromatosis; hemolytic anemia; acute phase of infectious kidney disease

Interactions
Chloramphenicol-induced bone marrow toxicity may cause increased iron levels

Pregnancy
C - Safety for use during pregnancy has not been established.

Precautions
Monitor for allergic reactions (eg, flushing, hypotension, nausea)

Drug Name
Iron sucrose (Venofer) -- Used to treat iron deficiency (in conjunction with erythropoietin) due to chronic hemodialysis. Iron deficiency is caused by blood loss during the dialysis procedure, increased erythropoiesis, and insufficient absorption of iron from the GI tract. Iron sucrose has shown a lower incidence of anaphylaxis than other parenteral iron products.

Adult Dose
5 mL (100 mg elemental iron) IV by slow injection or infusion during dialysis session; typically requires a minimum cumulative dose of 1000 mg of elemental iron over 10 consecutive dialysis sessions to achieve a favorable hemoglobin or hematocrit response; not to exceed 3 doses per wk

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; iron overload; anemia unrelated to iron deficiency

Interactions
Decreases bioavailability of orally administered iron

Pregnancy
B - Usually safe but benefits must outweigh the risks.

Precautions
May cause hypotension (related to IV administration rate or cumulative dose), cramps, headache, nausea, vomiting, diarrhea, or anaphylaxis

Drug Name
Ferric gluconate (Ferrlecit) -- Replaces iron found in hemoglobin, myoglobin, and specific enzyme systems. Allows transportation of oxygen via hemoglobin.

Adult Dose
125 mg elemental iron/10 mL IV; may require cumulative dose of 1 g elemental iron to achieve favorable response in patients receiving hemodialysis

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; hemochromatosis; hemolytic anemia

Interactions
Vitamin C may increase absorption of oral iron when administered concurrently; absorption of oral preparation of iron and tetracyclines decreased when administered concurrently; concurrent administration of H2 blockers or proton pump inhibitors may inhibit iron absorption

Pregnancy
B - Usually safe but benefits must outweigh the risks.

Precautions
Flushing and transient hypotension may occur; may augment hemodialysis-induced hypotension

Drug Category: Recombinant human erythropoietin -- Stimulates development of erythroid progenitor cells.

Drug Name
Darbepoetin (Aranesp) -- Erythropoiesis stimulating protein closely related to erythropoietin, a primary growth factor produced in kidney that stimulates development of erythroid progenitor cells. Mechanism of action is similar to that of endogenous erythropoietin, which interacts with stem cells to increase red cell production. Differs from epoetin alfa (recombinant human erythropoietin) in containing 5 N-linked oligosaccharide chains, whereas epoetin alfa contains 3. Has longer half-life than epoetin alfa (may be administered weekly or biweekly).

Adult Dose
0.45 mcg/kg IV/SC qwk initially; adjust dose (not to exceed 3 mcg/kg/wk) or frequency (eg, q2wk); to maintain target Hgb (not to exceed 12 g/dL); do not increase dose more frequently than qmo
Switching from epoetin alfa: Base dose on total weekly erythropoietin dose and frequency of administration

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity; uncontrolled hypertension

Interactions
None reported

Pregnancy
C - Safety for use during pregnancy has not been established.

Precautions
Elevation in Hgb >1 g/dL/2wk increases risk of MI, neurologic events (eg, seizures, stroke) and exacerbations of hypertension, CHF, thrombosis, ischemia, and edema; adverse effects include infection, hypertension, hypotension, myalgia, headache, and diarrhea (some of adverse events may be due to chronic renal failure or dialysis); severe skin rash may occur (rare)

Drug Category: Calcimimetic agents -- These agents reduce parathyroid hormone levels.

Drug Name
Cinacalcet (Sensipar) -- Directly lowers intact parathyroid hormone (iPTH) levels by increasing sensitivity of calcium sensing receptor on chief cell of parathyroid gland to extracellular calcium. Also results in concomitant serum calcium decrease. Indicated for secondary hyperparathyroidism in patients with chronic kidney disease on dialysis.

Adult Dose
30 mg PO qd initially; titrate upward slowly (no more frequent than q2-4wk intervals) by 30 mg increments to target iPTH of 150-300 pg/mL
Take with meals or immediately following; do not crush, chew or cut tablets

Pediatric Dose
Not established

Contraindications
Documented hypersensitivity

Interactions
Strong CYP450 2D6 inhibitor; may increase serum levels of CYP 2D6 substrates (eg, flecainide, vinblastine, thioridazine, tricyclic antidepressants); coadministration with CYP450 3A4 inhibitors (eg, ketoconazole, erythromycin, itraconazole)) may decrease cinacalcet clearance

Pregnancy
C - Safety for use during pregnancy has not been established.

Precautions
Serum calcium reduction may cause lowered seizure threshold, paresthesia, myalgia, cramping, and tetany; monitor calcium and phosphorus levels closely within 1 wk following initial dose or dose changes, and then monthly (secondary hyperparathyroidism) and q2 mo (parathyroid carcinoma); do not initiate treatment if serum calcium below 8.4 mg/dL; adynamic bone disease may occur if iPTH levels suppressed below 100 pg/mL; caution with hepatic impairment; common adverse effects include nausea and vomiting

 

FOLLOW-UP

Further Inpatient Care:

• Patients who develop potentially life-threatening complications of CKD should be hospitalized and closely monitored.

Further Outpatient Care:

• Patients with CKD should be referred to a nephrologist early in the course of their disease and have continued nephrologic follow-up until initiation of chronic renal replacement therapy.

• A multidisciplinary approach to care, including involvement of the nephrologist, primary care physician, renal dietitian, nurse, and social worker, should be initiated early in the course of CKD, with close patient follow-up.

Transfer:

• Patients with CKD acutely presenting with indications for dialytic therapy should be transferred to a hospital center where acute dialysis can be performed.

Prognosis:

• Patients with CKD generally progress to ESRD. The rate of progression depends on the underlying diagnosis, on the successful implementation of secondary preventative measures, and on the individual patient.

• Patients on chronic dialysis have a high incidence of morbidity and mortality.

• Patients with ESRD who undergo renal transplantation survive longer than those on chronic dialysis.

Patient Education:

• Patients with CKD should be educated about the importance of compliance with secondary preventative measures, natural disease progression, prescribed medications (highlighting their potential benefits and adverse effects), avoidance of nephrotoxins, diet, chronic renal replacement modalities, including peritoneal dialysis, hemodialysis, and transplantation, and permanent vascular access options for hemodialysis.

• For excellent patient education resources, visit eMedicine's
Diabetes Center. Also, see eMedicine's patient education article Chronic Kidney Failure.

MISCELLANEOUS

Medical/Legal Pitfalls:

• Early diagnosis and treatment of the underlying cause or/and institution of secondary preventative measures in CKD is imperative to try to delay, or possibly halt, progression. Early nephrologic referral is of extreme importance.

• Timely initiation of chronic renal replacement therapy is imperative to prevent the uremic complications of CKD that can lead to significant morbidity and death.

• In CKD, doses and intervals of drugs that are excreted or metabolized renally should be adjusted accordingly for the residual GFR. Some drugs are contraindicated in moderate-to-severe renal impairment because of potentially serious effects from drug or metabolite accumulation. Routine consultation of the appropriate references should be undertaken when prescribing any new drug to a patient with CKD.

Special Concerns:

• Female patients with advanced CKD commonly develop menstrual irregularities; women with ESRD are typically amenorrheic and infertile.

• Pregnancy in CKD can be associated with accelerated renal decline. In advanced CKD and ESRD, pregnancy is associated with markedly decreased fetal survival.

 

BIBLIOGRAPHY

• Adamson JW, Eschbach JW: Erythropoietin for end-stage renal disease. N Engl J Med 1998 Aug 27; 339(9): 625-7
[Medline].

Allon M: Hyperkalemia in end-stage renal disease: mechanisms and management. J Am Soc Nephrol 1995 Oct; 6(4): 1134-42[Medline].

Anderson S, Brenner BM: Effects of aging on the renal glomerulus. Am J Med 1986 Mar; 80(3): 435-42[Medline].

Bakris GL, Weir MR: Angiotensin-converting enzyme inhibitor-associated elevations in serum creatinine: is this a cause for concern? Arch Intern Med 2000 Mar 13; 160(5): 685-93[Medline].

Coresh J, Astor BC, Greene T: Prevalence of chronic kidney disease and decreased kidney function in the adult US population: Third National Health and Nutrition Examination Survey. Am J Kidney Dis 2003 Jan; 41(1): 1-12[Medline].

Delmez JA, Slatopolsky E: Hyperphosphatemia: its consequences and treatment in patients with chronic renal disease. Am J Kidney Dis 1992 Apr; 19(4): 303-17[Medline].

Fournier A, Moriniere P, Ben Hamida F, et al: Use of alkaline calcium salts as phosphate binder in uremic patients. Kidney Int Suppl 1992 Oct; 38: S50-61[Medline].

Hakim RM, Lazarus JM: Initiation of dialysis. J Am Soc Nephrol 1995 Nov; 6(5): 1319-28[Medline].

Hakim RM, Lazarus JM: Progression of chronic renal failure. Am J Kidney Dis 1989 Nov; 14(5): 396-401[Medline].

Hruska KA, Teitelbaum SL: Renal osteodystrophy. N Engl J Med 1995 Jul 20; 333(3): 166-74[Medline].

Hunsicker LG, Adler S, Caggiula A, et al: Predictors of the progression of renal disease in the Modification of Diet in Renal Disease Study. Kidney Int 1997 Jun; 51(6): 1908-19[Medline].

Innes A, Rowe PA, Burden RP, Morgan AG: Early deaths on renal replacement therapy: the need for early nephrological referral. Nephrol Dial Transplant 1992; 7(6): 467-71[Medline].

Jacobson HR: Chronic renal failure: pathophysiology. Lancet 1991 Aug 17; 338(8764): 419-23[Medline].

Jafar TH, Schmid CH, Landa M, et al: Angiotensin-converting enzyme inhibitors and progression of nondiabetic renal disease. A meta-analysis of patient-level data. Ann Intern Med 2001 Jul 17; 135(2): 73-87[Medline].

Joint National Committee: The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. JAMA 2003; 289: 2560-2571.

Jungers P, Zingraff J, Albouze G: Late referral to maintenance dialysis: detrimental consequences. Nephrol Dial Transplant 1993; 8(10): 1089-93[Medline].

Lazarus JM, Bourgoignie JJ, Buckalew VM: Achievement and safety of a low blood pressure goal in chronic renal disease. The Modification of Diet in Renal Disease Study Group. Hypertension 1997 Feb; 29(2): 641-50[Medline].

Levey AS, Coresh J, Balk E: National Kidney Foundation practice guidelines for chronic kidney disease: evaluation, classification, and stratification. Ann Intern Med 2003 Jul 15; 139(2): 137-47[Medline].

Levey AS, Bosch JP, Lewis JB: A more accurate method to estimate glomerular filtration rate from serum creatinine: a new prediction equation. Modification of Diet in Renal Disease Study Group. Ann Intern Med 1999 Mar 16; 130(6): 461-70[Medline].

Lewis EJ, Hunsicker LG, Bain RP: The effect of angiotensin-converting-enzyme inhibition on diabetic nephropathy. The Collaborative Study Group. N Engl J Med 1993 Nov 11; 329(20): 1456-62[Medline].

Madaio MP: Renal biopsy. Kidney Int 1990 Sep; 38(3): 529-43[Medline].

Mailloux LU: Hypertension in chronic renal failure and ESRD: prevalence, pathophysiology, and outcomes. Semin Nephrol 2001 Mar; 21(2): 146-56[Medline].

Mehrotra R, Nolph KD: Treatment of advanced renal failure: low-protein diets or timely initiation of dialysis? Kidney Int 2000 Oct; 58(4): 1381-8[Medline].

Mendelssohn DC, Cole EH: Outcomes of percutaneous kidney biopsy, including those of solitary native kidneys. Am J Kidney Dis 1995 Oct; 26(4): 580-5[Medline].

Modification of Diet in Renal Disease Study: Effects of diet and antihypertensive therapy on creatinine clearance and serum creatinine concentration in the Modification of Diet in Renal Disease Study. J Am Soc Nephrol 1996 Apr; 7(4): 556-66[Medline].

Muirhead N, Bargman J, Burgess E, et al: Evidence-based recommendations for the clinical use of recombinant human erythropoietin. Am J Kidney Dis 1995 Aug; 26(2 Suppl 1): S1-24[Medline].

National Kidney Foundation: K/DOQI clinical practice guidelines for chronic kidney disease: evaluation, classification, and stratification. Am J Kidney Dis 2002 Feb; 39(2 Suppl 1): S1-266[Medline].

Peterson JC, Adler S, Burkart JM: Blood pressure control, proteinuria, and the progression of renal disease. The Modification of Diet in Renal Disease Study. Ann Intern Med 1995 Nov 15; 123(10): 754-62[Medline].

Ruggenenti P, Schieppati A, Remuzzi G: Progression, remission, regression of chronic renal diseases. Lancet 2001 May 19; 357(9268): 1601-8[Medline].

Schmidt RJ, Domico JR, Sorkin MI: Early referral and its impact on emergent first dialyses, health care costs, and outcome. Am J Kidney Dis 1998 Aug; 32(2): 278-83[Medline].

Sesso R, Belasco AG: Late diagnosis of chronic renal failure and mortality on maintenance dialysis. Nephrol Dial Transplant 1996 Dec; 11(12): 2417-20[Medline].

Slatopolsky E, Berkoben M, Kelber J: Effects of calcitriol and non-calcemic vitamin D analogs on secondary hyperparathyroidism. Kidney Int Suppl 1992 Oct; 38: S43-9[Medline].

St Peter WL, Schoolwerth AC, McGowan T: Chronic kidney disease: issues and establishing programs and clinics for improved patient outcomes. Am J Kidney Dis 2003 May; 41(5): 903-24[Medline].

United States Renal Data System: USRDS 2004 Annual Data Report. National Institute of Diabetes and Digestive and Kidney Diseases. Bethesda, MD: The National Institutes of Health; 2004.

Uribarri J: Acidosis in chronic renal insufficiency. Semin Dial 2000 Jul-Aug; 13(4): 232-4[Medline].

Walser M: Progression of chronic renal failure in man. Kidney Int 1990 May; 37(5): 1195-210[Medline].

Walser M, Mitch WE, Maroni BJ, Kopple JD: Should protein intake be restricted in predialysis patients? Kidney Int 1999 Mar; 55(3): 771-7[Medline].

Warnock DG: Uremic acidosis. Kidney Int 1988 Aug; 34(2): 278-87[Medline].

Webb JA: Ultrasonography in the diagnosis of renal obstruction. BMJ 1990 Oct 27; 301(6758): 944-6[Medline].

Xue JL, Ma JZ, Louis TA: Forecast of the number of patients with end-stage renal disease in the United States to the year 2010. J Am Soc Nephrol 2001 Dec; 12(12): 2753-8[Medline].

Zeller K, Whittaker E, Sullivan L, et al: Effect of restricting dietary protein on the progression of renal failure in patients with insulin-dependent diabetes mellitus. N Engl J Med 1991 Jan 10; 324(2): 78-84[Medline].

Reference Link:

http://www.emedicine.com/med/topic374.htm